The present subject matter relates to electronic displays. More specifically, the present subject matter relates to circuits to control arrays of electro-optical elements.
Some types of electronic displays may utilize relatively high voltages (>5-10V). Circuits for displays such as electrophoretic, cholesteric liquid crystal, and other low-power, bistable displays, as well as more traditional liquid crystal displays (LCD), may be designed to control individual regions of the display using a voltage level or electric field created across the individual regions. The individual regions may commonly be referred to as a pixel, a sub-pixel, a picture element (pel) or an electro-optical element.
These electronic displays may be refreshed by storing particular amounts of charge into capacitances associated with the electro-optical elements of an individual row, then repeating this operation for the other rows of the display. The number of rows of pixels, in combination with the rate that the display is updated, may determine the amount of time that is available to store charge into the associated capacitances.
Voltage-driven displays may have a single thin film transistor (TFT) a teach electro-optical element. However, due to the relatively high voltage that may be present across the TFT for some displays, or relatively poor TFT performance due to materials used or fabrication methods, many TFTs used for displays may have a high leakage current in some designs, the TFT may be designed to have lower leakage, but that may result in lower on-state current. Either high leakage or lower on-state current may limit resolution, display size, gray scale capability, or other display characteristics, due to the limited time available to charge the capacitances associated with individual electro-optical elements.